Post-Installed Sleeve Device For Compensating Loss Of Shear Capacity

ABSTRACT

A post-installed sleeve device is provided for compensating loss of shear capacity of a concrete slab due to a hole drilled in the concrete slab. The sleeve device includes a hollow member of, for example, a cylindrical shape, and a lower sandwich member and an upper sandwich member shaped, for example, as ring members. The hollow member is inserted into the drilled hole such that an upper section of the hollow member extends above a top surface of the concrete slab. The lower sandwich member includes an inner edge rigidly attached to a bottom edge of the hollow member. The upper sandwich member includes an inner edge engageably connected to the upper section of the hollow member. The upper sandwich member and the lower sandwich member sandwich the concrete slab surrounding the drilled hole therebetween for compensating the lost shear capacity of the concrete slab due to the drilled hole.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of provisionalpatent application No. 61/858,123 titled “Post-installed Sleeve DeviceFor Compensating Loss Of Shear Capacity”, filed in the United StatesPatent and Trademark Office on Jul. 25, 2013. The specification of theabove referenced patent application is incorporated herein by referencein its entirety.

BACKGROUND

Concrete structures, for example, reinforced concrete flat slabs orconcrete slabs are extensively used in the building constructionindustry. In conventional building renovations, vertical utility pipesare typically positioned adjacent to concrete columns due toarchitectural or mechanical requirements. To position vertical utilitypipes in a concrete slab, holes have to be created in the existingconcrete slab. Manual drilling is a widely adopted method to create ahole in a concrete slab, where a drill bit of a specific size is used todrill a hole of a predetermined radius and depth in the concrete slab.However, holes created by drilling reduce the shear capacity of theconcrete slabs. Engineers must recalculate moment and shear capacitiesof the concrete slabs when sleeves are placed in close proximity tosupports or concrete columns. In many cases, structural changes arerequired to compensate for the loss of shear capacity caused by pipepenetrations. A pipe penetration in a concrete slab may substantiallyreduce the shear capacity of the concrete slab and in some cases cause ashear failure.

Hence, there is a long felt but unresolved need for a post-installedsleeve device that compensates for loss of shear capacity of areinforced concrete slab, after a hole is drilled in the reinforcedconcrete slab proximal to a supporting column. Moreover, there is a needfor a post-installed sleeve device that allows architects and mechanicalengineers more flexibility in locating mechanical piping with minimalwork and effort.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further disclosed in the detailed descriptionof the invention. This summary is not intended to identify key oressential inventive concepts of the claimed subject matter, nor is itintended for determining the scope of the claimed subject matter.

The post-installed sleeve device disclosed herein addresses the abovestated need for compensating loss of shear capacity of a reinforcedconcrete slab, after a hole is drilled in the reinforced concrete slabproximal to a supporting column. Moreover, the sleeve device disclosedherein allows architects and mechanical engineers more flexibility inlocating mechanical piping with minimal work and effort. The sleevedevice disclosed herein is a device, for example, made of metal used inan existing cast-in-place concrete structure to reinforce shear capacityof the concrete structure by attaching two sandwich members, forexample, ring shaped members to an upper section and a bottom edge ofthe sleeve device. The sleeve device disclosed herein is configured totransfer shear stresses in the concrete slab.

The sleeve device disclosed herein comprises a hollow member, forexample, of a generally cylindrical shape, a lower sandwich member, andan upper sandwich member. The hollow member is inserted into a holedrilled in the concrete slab such that an upper section of the insertedhollow member extends above the top surface of the concrete slab. Thelower sandwich member comprises an inner edge rigidly attached to abottom edge of the hollow member. The upper sandwich member comprises aninner edge engageably connected to the upper section of the hollowmember. The upper sandwich member and the lower sandwich member areconfigured to sandwich the concrete slab surrounding the drilled holetherebetween for compensating the lost shear capacity of the concreteslab due to the drilled hole. In an embodiment, the upper sandwichmember and the lower sandwich member are configured as an upper ringmember and a lower ring member respectively. In this embodiment, thehollow member comprises a threaded upper section, and the upper ringmember comprises an inner threaded edge that is engageably connected tothe threaded upper section of the hollow member.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe invention, is better understood when read in conjunction with theappended drawings. For the purpose of illustrating the invention,exemplary constructions of the invention are shown in the drawings.However, the invention is not limited to the specific methods andstructures disclosed herein. The description of a method step or astructure referenced by a numeral in a drawing carries over to thedescription of that method step or structure shown by that same numeralin any subsequent drawing herein.

FIG. 1 exemplarily illustrates a top perspective view of apost-installed sleeve device for compensating lost shear capacity of aconcrete slab due to a hole drilled in the concrete slab.

FIG. 2 exemplarily illustrates a front elevation view of thepost-installed sleeve device.

FIG. 3A exemplarily illustrates a sectional view of the post-installedsleeve device taken along a sectional line A-A shown in FIG. 1.

FIG. 3B exemplarily illustrates an enlarged view of a portion of thepost-installed sleeve device marked X in FIG. 3A, showing threadedsections of the post-installed sleeve device.

FIG. 4 exemplarily illustrates a top plan view of the post-installedsleeve device.

FIGS. 5A-5C exemplarily illustrate insertion and assembly of thepost-installed sleeve device in a hole drilled in a concrete slab forcompensating loss of shear capacity of the concrete slab due to thedrilled hole.

FIG. 6 exemplarily illustrates a top perspective view of multiplepost-installed sleeve devices positioned in a concrete slab proximal toa supporting column.

FIG. 7 exemplarily illustrates a top plan view, showing post-installedsleeve devices of different diameters positioned in a concrete slabproximal to a supporting column.

FIG. 8 illustrates a method for compensating loss of shear capacity of aconcrete slab due to a hole drilled in the concrete slab.

FIG. 9 exemplarily illustrates a side view of a concrete slab with thepost-installed sleeve device inserted into a hole drilled in theconcrete slab, showing a shear critical section of the concrete slab.

FIGS. 10A-10B exemplarily illustrate top plan views of a supportingcolumn and a concrete slab of different dimensions, showing shearcritical sections of the concrete slabs.

FIG. 10C exemplarily illustrates a top plan view of a supporting columnand a concrete slab with a hole drilled proximal to the supportingcolumn, and showing a shear critical section of the concrete slab.

FIG. 10D exemplarily illustrates a top plan view of a supporting columnand a concrete slab with the post-installed sleeve device inserted intoa hole drilled in the concrete slab, proximal to the supporting column,and showing a shear critical section of the concrete slab.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 exemplarily illustrates a top perspective view of apost-installed sleeve device 100 for compensating lost shear capacity ofa concrete slab 501 due to a hole 502 drilled in the concrete slab 501exemplarily illustrated in FIGS. 5A-5C. As used herein, “shear capacity”refers to maximum shear stress that a concrete structure, for example,the concrete slab 501 can withstand before shear failure of the concretestructure. Also, as used herein, “shear stress” refers to an externalforce per unit area acting on a structure or a surface parallel to aplane of the structure or the surface. The sleeve device 100 disclosedherein is, for example, a steel sleeve device used in an existingcast-in-place reinforced concrete slab 501.

The sleeve device 100 is made of, for example, multiple types of steelwith multiple tensile strengths, an alloy, or other structural material.The sleeve device 100 disclosed herein comprises a hollow member 101, alower sandwich member, for example, a lower ring member 103, and anupper sandwich member, for example, an upper ring member 104. As usedherein, “sandwich member” refers to a mechanical structure used forrigidly sandwiching the concrete slab 501 surrounding the drilled hole502. The sandwich member is, for example, a ring shaped member, a loadtransfer plate, etc. For purposes of illustration, the detaileddescription refers to the sandwich members being configured as ringmembers 103 and 104 for transferring shear stresses through the hollowmember 101 to compensate loss of shear capacity of the concrete slab 501due to the drilled hole 502; however, the scope of the sleeve device 100disclosed herein is not limited to the sandwich members being configuredas the ring members 103 and 104, but may be extended to include sandwichmembers configured as alternate affixations comprising, for example,plates, bars, bonding agents such as epoxy adhesives, etc., and otherfunctionally equivalent structures to transfer shear stresses from theconcrete slab 501 through the hollow member 101. In an embodiment, thelower sandwich member and the upper sandwich member can be of the sametype, for example, ring members 103 and 104, or of different types, forexample, a combination of a ring member 103 or 104 and a plate, acombination of a ring member 103 or 104 and bars, etc.

As exemplarily illustrated in FIG. 1, the hollow member 101 is of agenerally cylindrical shape. A cross section B-B of the hollow member101 is, for example, of a circular geometric shape or another geometricshape that allows the upper sandwich member, for example, 104 to beengageably connected to the upper section 101 d of the hollow member101. The hollow member 101 defines an inner void 102 therewithin forinserting, for example, plumbing piping, mechanical piping, heavy gaugewiring, etc. The hollow member 101 is configured in multiple shapes thatallow multiple insertions, for example, mechanical structures andelectrical components to be inserted through the inner void 102 of thehollow member 101 that is inserted into the hole 502 drilled in theconcrete slab 501, or insertions that require an opening for mechanical,architectural, or other purposes.

The hollow member 101 is inserted into a hole 502 drilled in theconcrete slab 501 exemplarily illustrated in FIGS. 5A-5C. The hollowmember 101 comprises a threaded upper section 101 d proximal to a topedge 101 a of the hollow member 101. The threaded upper section 101 d ofthe inserted hollow member 101 extends above a top surface 501 a of theconcrete slab 501. The lower ring member 103 comprises an inner edge 103a also exemplarily illustrated in FIG. 3A, rigidly attached to a bottomedge 101 b of the hollow member 101. The upper ring member 104 comprisesan inner threaded edge 104 a engageably connected to the threaded uppersection 101 d of the hollow member 101. In an embodiment, the sleevedevice 100 comprises multiple gripping members 105 positioned on andattached to an upper surface 104 b of the upper ring member 104. Thegripping members 105 provide a grip for engageably connecting the upperring member 104 to the hollow member 101. In an embodiment, the grippingmembers 105 are configured as rectangular tabs. The upper ring member104 and the lower ring member 103 sandwich the concrete slab 501surrounding the drilled hole 502 therebetween for compensating the lostshear capacity of the concrete slab 501 due to the drilled hole 502. Thelower ring member 103 and the upper ring member 104 transfer shearstresses through the hollow member 101 to compensate loss of the shearcapacity of the concrete slab 501 due to the drilled hole 502. In anembodiment, the shear stresses are transferred from the concrete slab501 to the lower ring member 103 and the upper ring member 104 of thesleeve device 100, through the hollow member 101 as disclosed in thedetailed description of FIG. 9.

FIG. 2 exemplarily illustrates a front elevation view of thepost-installed sleeve device 100. The sleeve device 100 disclosed hereinis constructed by attaching two sandwich members, for example, the ringmembers 103 and 104 or plates to the bottom edge 101 b and the threadedupper section 101 d of the hollow member 101 respectively. The hollowmember 101 is inserted into a hole 502 drilled in a concrete slab 501exemplarily illustrated in FIGS. 5A-5C, to reinforce the concrete slab501. The hollow member 101 is, for example, made of steel. The lowerring member 103 is, for example, a metallic ring shaped plate welded tothe bottom edge 101 b of the hollow member 101. Welding is performedbetween the inner edge 103 a of the lower ring member 103 exemplarilyillustrated in FIG. 1, and the bottom edge 101 b of the hollow member101. The upper ring member 104 is threadably engaged to the uppersection 101 d of the hollow member 101.

FIG. 3A exemplarily illustrates a sectional view of the post-installedsleeve device 100 taken along a sectional line A-A shown in FIG. 1. FIG.3B exemplarily illustrates an enlarged view of a portion of thepost-installed sleeve device 100 marked X in FIG. 3A, showing threadedsections, for example, a threaded upper section 101 d of the hollowmember 101 and a threaded section 104 d on an inner threaded edge 104 aof the upper ring member 104 of the post-installed sleeve device 100.The upper ring member 104 is, for example, a metallic ring shaped platewith the threaded section 104 d defined along the inner threaded edge104 a of the ring shaped plate. The threaded section 104 d along theinner threaded edge 104 a of the upper ring member 104 is engaged withthe threaded upper section 101 d of the hollow member 101 within apredetermined thickness 501 g of the concrete slab 501 exemplarilyillustrated in FIG. 9.

FIG. 4 exemplarily illustrates a top plan view of the post-installedsleeve device 100. The upper ring member 104 and the lower ring member103 of the sleeve device 100 extend outward from an outer wall 101 c ofthe hollow member 101 of the sleeve device 100 as exemplarilyillustrated in FIGS. 1-2. An inner void 102 defined within the hollowmember 101 of the sleeve device 100 allows insertions, for example,plumbing piping, mechanical piping, heavy gauge wiring, etc., throughthe hole 502 drilled in the concrete slab 501 exemplarily illustrated inFIGS. 5A-5C. The lower ring member 103 and the upper ring member 104attach the sleeve device 100 to the concrete slab 501. The grippingmembers 105 attached to the upper surface 104 b of the upper ring member104 are also exemplarily illustrated in FIG. 4.

FIGS. 5A-5C exemplarily illustrate insertion and assembly of thepost-installed sleeve device 100 in a hole 502 drilled in a concreteslab 501 for compensating loss of shear capacity of the concrete slab501 due to the drilled hole 502. As exemplarily illustrated in FIG. 5A,a hole 502 is drilled in the concrete slab 501 using a drill apparatus503. After the hole 502 is drilled in the concrete slab 501, the sleevedevice 100 is inserted through the drilled hole 502 from a lower surface501 b of the concrete slab 501 such that the threaded upper section 101d of the inserted hollow member 101 extends above a top surface 501 a ofthe concrete slab 501 as exemplarily illustrated in FIGS. 5B-5C. Theupper surface 103 b of the lower ring member 103 is held in rigidcontact with the lower surface 501 b of the concrete slab 501. The innerthreaded edge 104 a of the upper ring member 104 exemplarily illustratedin FIG. 3B, is engageably connected to the threaded upper section 101 dof the inserted hollow member 101 to sandwich the concrete slab 501surrounding the drilled hole 502 in the concrete slab 501 between theupper ring member 104 and the lower ring member 103. The grippingmembers 105 are used for tightening the upper ring member 104 down tothe concrete slab 501.

In an embodiment, on inserting the hollow member 101 into the drilledhole 502, if there is a gap 504 defined between the outer wall 101 c ofthe hollow member 101, the upper surface 103 b of the lower ring member103, and an inner surface 501 c of the concrete slab 501, grout isfilled in the gap 504 to ensure full contact of the sleeve device 100with the drilled hole 502, if required. After filling the grout in thegap 504, the upper ring member 104 is engageably connected to the hollowmember 101 to sandwich the concrete slab 501 surrounding the drilledhole 502 between the upper ring member 104 and the lower ring member103.

FIG. 6 exemplarily illustrates a top perspective view of multiplepost-installed sleeve devices 100 a, 100 b, and 100 c positioned in aconcrete slab 501 proximal to a supporting column 601. The sleevedevices 100 a, 100 b, and 100 c are positioned adjacent to each other inthe concrete slab 501 with the threaded upper section 101 d of eachhollow member 101 extending above a top surface 501 a of the concreteslab 501. As exemplarily illustrated in FIG. 6, the sleeve device 100 cis positioned in a perpendicular direction with respect to the other twosleeve devices 100 a and 100 b. The sleeve devices 100 a, 100 b, and 100c are used in an existing concrete slab 501 to increase slab shearcapacity when penetrations, for example, drill holes 502 exemplarilyillustrated in FIGS. 5A-5B, are made in the vicinity of supportingcolumns 601. The lower ring member 103 and the upper ring member 104increase the size of a shear critical section 501 f exemplarilyillustrated in FIG. 9. As used herein, “shear critical section” refersto a section in the concrete slab 501, which defines a slab-column jointpunching shear capacity. Also, as used herein, the term “shear capacity”refers to an ability of a concrete structure to withstand a maximumshear stress before occurrence of a shear failure in the concretestructure. The lower ring member 103 and the upper ring member 104 canprevent shear failure within a predefined threshold range of the sleevedevice 100 a, or 100 b, or 100 c, thereby reinforcing the shear capacityof the concrete slab 501. The “threshold range” of the sleeve device 100a, or 100 b, or 100 c is defined by the American Concrete Institute(ACI) in Building Code Requirements for Structural Concrete, ACI 318,chapter 11.

Consider an example where a concrete slab 501 is positioned such that anedge 501 e of the concrete slab 501 is proximal to a supporting column601, and an edge 501 d of the concrete slab 501 is distal to thesupporting column 601. A hole 502 exemplarily illustrated in FIGS.5A-5B, proximal to the supporting column 601, is drilled in the concreteslab 501. After drilling the hole 502, the concrete slab 501 experiencesshear stresses 602 and 603 around the drilled hole 502 that areperpendicular to the top surface 501 a of the concrete slab 501. Asloads on the edge 501 d of the concrete slab 501 increase, the shearstresses 602 and 603 at the drilled hole 502 also increase, therebyincreasing risk of a shear failure in the concrete slab 501 at thedrilled hole 502. To prevent the shear failure of the concrete slab 501,the post-installed sleeve device, for example, 100 c exemplarilyillustrated in FIG. 6, is inserted into the drilled hole 502 such thatthe upper surface 103 b of the lower ring member 103 is held in rigidcontact with the lower surface 501 b of the concrete slab 501. The innerthreaded edge 104 a of the upper ring member 104 is then engageablyconnected to the threaded upper section 101 d of the hollow member 101as exemplarily illustrated in FIG. 3B. The upper ring member 104 and thelower ring member 103 of the sleeve device 100 c sandwich the concreteslab 501 surrounding the drilled hole 502, thereby increasing area ofthe shear critical section 501 f exemplarily illustrated in FIG. 9,around the drilled hole 502 in the concrete slab 501.

An average shear stress (v) is defined as force (F) per unit area (A) inaccordance with the formula below:

ν≡(F/A)

The shear force F acts on an area A. This area A is the area of theshear critical section 501 f around the drilled hole 502 as exemplarilyillustrated in FIG. 10C. As the average shear stress ν is inverselyproportional to the area A, the shear stress v increases if the area Ais decreased. Hence, drilling a hole 502 in the concrete slab 501proximal to a supporting column 601 reduces the area A, therebyincreasing the shear stress ν. The lost shear capacity can be defined asthe area of the drilled hole 502 multiplied by the original shear stressv that the concrete slab 501 experienced before drilling the hole 502.By introducing the sleeve device 100 a, or 100 b, or 100 c into thedrilled hole 502, the lost shear capacity can be compensated for throughthe added shear capacity of the sleeve device 100 a, or 100 b, or 100 c.Hence, as a result of sandwiching of the concrete slab 501 surroundingthe drilled hole 502, by the upper ring member 104 and the lower ringmember 103 of the sleeve device 100 a, or 100 b, or 100 c, the area A orthe area of the shear critical section 501 f around the drilled hole 502increases, thereby decreasing the shear stresses 602 and 603 at thedrilled hole 502. Since the upper ring member 104 and the lower ringmember 103 increase the area of the shear critical section 501 f aroundthe drilled hole 502 in the concrete slab 501, the concentration of theshear stresses 602 and 603 exerted at the drilled hole 502 decreases.The sleeve device 100 a, and/or 100 b, and/or 100 c thus strengthens theshear capacity of the concrete slab 501 surrounding the drilled hole 502to mitigate risk of a shear failure of the concrete slab 501 bycompensating the lost shear capacity of the concrete slab 501 due to thedrilled hole 502.

FIG. 7 exemplarily illustrates a top plan view, showing post-installedsleeve devices 100 a and 100 b of different diameters D1 and D2respectively, positioned in a concrete slab 501 exemplarily illustratedin FIG. 6, proximal to a supporting column 601. In an embodiment, thehollow member 101 of the sleeve device 100 a or 100 b is configured asan extensible hollow member 101 to be inserted into a drilled hole 502exemplarily illustrated in FIGS. 5A-5B, of different dimensions and toenable the upper ring member 104 and the lower ring member 103 of eachof the sleeve devices 100 a and 100 b to adjustably sandwich theconcrete slab 501 surrounding the drilled hole 502 of multipledimensions. The diameters of the extensible hollow members 101 of thepost-installed sleeve devices 100 a and 100 b may be D1 or D2 based onmultiple parameters, for example, physical dimensions such as diameteror circumference of the drilled hole 502, thickness 501 g of theconcrete slab 501 exemplarily illustrated in FIG. 9, etc.

FIG. 8 illustrates a method for compensating loss of shear capacity of aconcrete slab 501 due to a hole 502 drilled in the concrete slab 501exemplarily illustrated in FIGS. 5A-5C. A post-installed sleeve device100 comprising a hollow member 101, an upper sandwich member, forexample, an upper ring member 104, and a lower sandwich member, forexample, a lower ring member 103 as exemplarily illustrated in FIGS. 1-4and as disclosed in the detailed description of FIGS. 1-7, is provided801. The hollow member 101 of the sleeve device 100 is inserted 802 intothe drilled hole 502 of the concrete slab 501 to rigidly contact anupper surface 103 b of the lower sandwich member of the sleeve device100 with a lower surface 501 b of the concrete slab 501. The uppersection 101 d of the inserted hollow member 101 extends above a topsurface 501 a of the concrete slab 501. An inner edge 104 a of the uppersandwich member of the sleeve device 100 is engageably connected 803 tothe upper section 101 d of the inserted hollow member 101. The uppersandwich member and the lower sandwich member sandwich 804 the concreteslab 501 surrounding the drilled hole 502 therebetween for compensatingthe loss of shear capacity of the concrete slab 501 due to the drilledhole 502. Due to the sandwiching 804 of the concrete slab 501surrounding the drilled hole 502 by the upper sandwich member and thelower sandwich member of the sleeve device 100, a shear stress istransferred 804 a through the concrete slab 501, thereby producing acompressive force caused by shear in the concrete slab 501 on an uppersurface 103 b of the lower sandwich member. As used herein, “compressiveforce” refers to a force resulting from compression of two membersagainst each other, causing transfer of load through bearing from onemember to the other member. For example, a compressive force resultsfrom the compression in between the lower surface 501 b of the concreteslab 501 and the upper surface 103 b of the lower ring member 103exemplarily illustrated in FIG. 9. The shear stress in the concrete slab501 causes the compressive force. The compressive force is thenconverted 804 b to a shear stress from the lower sandwich member to theupper sandwich member through the outer wall 101 c of the hollow member101. The shear stress is then converted 804 c to a compressive forcefrom the lower surface 104 c of the upper sandwich member. Thecompressive force is transferred 804 c to the top surface 501 a of theconcrete slab 501. The compressive force is then converted 804 d to ashear stress which is transferred 804 d to a supporting column 601exemplarily illustrated in FIG. 9.

FIG. 9 exemplarily illustrates a side view of a concrete slab 501 withthe post-installed sleeve device 100 inserted into a hole 502 drilled inthe concrete slab 501 exemplarily illustrated in FIGS. 5A-5B, showing ashear critical section 501 f of the concrete slab 501. The shearcritical section 501 f is defined as an area located at a distance(d/2), referenced by 501 h in FIG. 9, from a supporting column 601,where “d” is the thickness 501 g of the concrete slab 501. Thepositioning of the shear critical section 501 f in the concrete slab 501at a distance “y” from the supporting column 601 is therefore, definedby a 1:2 slope triangle of height equal to the thickness 501 g of theconcrete slab 501 and base 501 h equal to half of the thickness 501 g ofthe concrete slab 501, where “y” is the hypotenuse of the 1:2 slopetriangle. The sandwiching of the concrete slab 501 surrounding thedrilled hole 502 by the upper ring member 104 and the lower ring member103 of the sleeve device 100, transfers a shear stress 901 through theconcrete slab 501, thereby producing a compressive force 902 on an uppersurface 103 b of the lower ring member 103. The compressive force 902 isthen converted to a shear stress 903 from the lower ring member 103 tothe upper ring member 104 through an outer wall 101 c of the hollowmember 101. The shear stress 903 is then converted to a compressiveforce 904 from the lower surface 104 c of the upper ring member 104. Thecompressive force 904 is transferred to the top surface 501 a of theconcrete slab 501. Thus, the compressive force 902 occurs distal to thesupporting column 601, while the compressive force 904 occurs proximalto the supporting column 601. The concrete slab 501 imposes thecompressive force 902 from the lower surface 501 b of the concrete slab501 onto the upper surface 103 b of the lower ring member 103, and thesleeve device 100 imposes the compressive force 904 from the lowersurface 104 c of the upper ring member 104 onto the top surface 501 a ofthe concrete slab 501. The compressive force 904 is converted to a shearstress 905. The shear stress 905 is transferred to the supporting column601. Thus, by sandwiching the concrete slab 501 at the drilled hole 502,the shear stress 901 distal to the supporting column 601 is transferredthrough the hollow member 101 and proximal to the supporting column 601.

FIGS. 10A-10B exemplarily illustrate top plan views of a supportingcolumn 601 and a concrete slab 501 of different dimensions, showingshear critical sections 501 f of the concrete slabs 501. The concreteslabs 501 exemplarily illustrated in FIGS. 10A-10B are free ofpenetrations. Consider an example where a concrete slab 501 of thickness(d), for example, 1 foot (′), that is, 12 inches (″) is supported by asupporting column 601 as exemplarily illustrated in FIG. 9. Consider theshear critical section 501 f to be at a distance (d/2) away from thesupporting column 601 and is therefore 6″ from the supporting column601. The area (A) of the shear critical section 501 f can be calculatedby multiplying the perimeter (P) of the shear critical section 501 f ata distance (d/2) from the supporting column 601 with the thickness (d)of the concrete slab 501 in accordance with the formula below:

A=(P*d)

Therefore, as exemplarily illustrated in FIG. 10A, the area (A) of theshear critical section 501 f is [(34″+34″+31″+31″)*12″]=1560 squareinches.

Consider another example where the concrete slab 501 of thickness (d)12″ is supported by a supporting column 601 of dimensions 1′ by 1′, thatis, 12″ by 12″ as exemplarily illustrated in FIG. 10B. Consider theshear critical section 501 f to be at a distance (d/2) away from thesupporting column 601 and is therefore 6″ from the supporting column601. The perimeter (P) of the shear critical section 501 f can becalculated as 2′*4, that is, 24″*4. The area (A) of the shear criticalsection 501 f is a multiplication product of the perimeter (P) of theshear critical section 501 f and the thickness (d) of the concrete slab501. Therefore, the area (A) of the shear critical section 501 f is[(24″*4)*12″]=1152 square inches.

Nominal shear capacity (Vn) of the concrete slab 501 at the supportingcolumn 601 is the sum of shear capacity (Vc) of the concrete slab 501and shear capacity (Vs) of shear reinforcement, that is, the sleevedevice 100 in accordance with the formula below:

Vn=Vc+Vs

The shear capacity (Vc) of the concrete slab 501 is 4 times themultiplication product of the area (A) of the shear critical section 501f and the square root of the strength (f′c) of the concrete slab 501 inaccordance with the formula below:

Vc=A*4*√{square root over (f′c)}

where f′c is the strength of the concrete slab 501, for example, about5000 pounds per square inch (psi). Therefore, the shear capacity (Vc) ofthe concrete slab 501 having the shear critical section 501 fexemplarily illustrated in FIG. 10B, is 1152*4*√5000=325835 lbs. Theshear capacity (Vs) of the sleeve device 100 is zero since the concreteslab 501 exemplarily illustrated in FIG. 10B, is free of penetrationsand therefore free of the sleeve device 100. Therefore, the nominalshear capacity (Vn) of the concrete slab 501 at the supporting column601 is 325835+0=325835 lbs.

FIG. 10C exemplarily illustrates a top plan view of a supporting column601 and a concrete slab 501 with a hole 502 drilled proximal to thesupporting column 601, and showing a shear critical section 501 f of theconcrete slab 501. Consider an 8″ core hole 502 drilled in the concreteslab 501 of thickness (d) 12″ having a strength of 5000 pounds persquare inch (psi) as exemplarily illustrated in FIG. 10C. The area (A)of the shear critical section 501 f is then calculated asA=[(24″*4)−8″]*12″=1056 square inches. The shear capacity (Vc) of theconcrete slab 501 can then be calculated as 1056*4*√5000=298682 lbs.Therefore, the nominal shear capacity (Vn) of the concrete slab 501 atthe supporting column 601 is 298682+=298682 lbs because the sleevedevice 100 is not inserted into the hole 502. Thus, the 8″ core drilledhole 502 reduces the nominal shear capacity (Vn) of the concrete slab501 at the supporting column 601 by 27153 lbs.

FIG. 10D exemplarily illustrates a top plan view of a supporting column601 and a concrete slab 501 with the post-installed sleeve device 100inserted into a hole 502 drilled in the concrete slab 501 exemplarilyillustrated in FIG. 10C, proximal to the supporting column 601, andshowing a shear critical section 501 f of the concrete slab 501. Thering members 103 and 104 of the sleeve device 100, exemplarilyillustrated in FIG. 1, are configured to sandwich the concrete slab 501surrounding the drilled hole 502, thereby compensating for the lostnominal shear capacity (Vn) of the concrete slab 501 at the supportingcolumn 601 due to the drilled hole 502. The relatively stiffer sleevedevice 100 confines the sandwiched concrete slab 501 surrounding thedrilled hole 502, thereby eliminating shear failure within the confinedconcrete slab 501 surrounding the drilled hole 502. Thus, the sleevedevice 100 bridges the penetration created in the concrete slab 501 dueto the drilled hole 502 and increases the perimeter (P) of the shearcritical section 501 f of the slab-column connection. Consider thesleeve device 100 is a rigid sleeve device and the associateddeformation of the sleeve device 100 is negligible under shear forces.The enhanced shear capacity of the sleeve device 100 that is required tocompensate the lost nominal shear capacity (Vn) is controlled by thethickness of the ring members 103 and 104 of the sleeve device 100. Whenthe sleeve device 100 is inserted into the drilled hole 502 and isconfigured to provide for the lost nominal shear capacity (Vn)=27153 lbsof the concrete slab 501 due to the drilled hole 502, the total nominalshear capacity (Vn) of the concrete slab 501 at the supporting column601 becomes equal to or larger than the nominal shear capacity(Vn)=325835 lbs of the concrete slab 501 at the supporting column 601before penetration of the concrete slab 501 with a drilled hole 502.Thus, the sleeve device 100 compensates the lost shear capacity of theconcrete slab 501 due to the drilled hole 502.

Consider an example where a sleeve device 100 is configured as a steelsleeve device to provide a shear capacity (Vs)=27153 lbs forcompensating the lost nominal shear capacity (Vn) of the concrete slab501 at the supporting column 601. To provide this compensation, steelarea (As) of each of the ring members 103 and 104 of the steel sleevedevice 100 exemplarily illustrated in FIGS. 1-2, is configured inaccordance with the formula below:

As=Vs/(0.4*ft)

where “fy” is the design yield strength of the steel used to configurethe ring members 103 and 104. Consider “fy” as 60000 psi. Therefore, thesteel area (As) is [(27153)/(0.4* 60000)]=1.13 square inches. As long aseach of the ring members 103 and 104 of the sleeve device 100 isconfigured with the area (As) required for effective shear forcetransfer width, the shear capacity (Vn) lost due to penetration of theconcrete slab 501 with the drilled hole 502 can be compensated.

The foregoing examples have been provided merely for the purpose ofexplanation and are in no way to be construed as limiting of the presentinvention disclosed herein. While the invention has been described withreference to various embodiments, it is understood that the words, whichhave been used herein, are words of description and illustration, ratherthan words of limitation. Further, although the invention has beendescribed herein with reference to particular means, materials, andembodiments, the invention is not intended to be limited to theparticulars disclosed herein; rather, the invention extends to allfunctionally equivalent structures, methods and uses, such as are withinthe scope of the appended claims. Those skilled in the art, having thebenefit of the teachings of this specification, may effect numerousmodifications thereto and changes may be made without departing from thescope and spirit of the invention in its aspects.

I claim:
 1. A sleeve device for compensating loss of shear capacity of aconcrete slab due to a hole drilled in said concrete slab, said sleevedevice comprising: a hollow member inserted into said drilled hole, saidhollow member comprising an upper section extending above a top surfaceof said concrete slab; a lower sandwich member comprising an inner edgerigidly attached to a bottom edge of said hollow member; and an uppersandwich member comprising an inner edge engageably connected to saidupper section of said hollow member, wherein said upper sandwich memberand said lower sandwich member are configured to sandwich said concreteslab surrounding said drilled hole therebetween for compensating saidloss of said shear capacity of said concrete slab due to said drilledhole.
 2. The sleeve device of claim 1, wherein said upper sandwichmember and said lower sandwich member are configured to increase area ofa shear critical section around said drilled hole in said concrete slabfor compensating said loss of said shear capacity of said concrete slabdue to said drilled hole.
 3. The sleeve device of claim 1, wherein saidhollow member is of a generally cylindrical shape.
 4. The sleeve deviceof claim 1, wherein a cross section of said hollow member is of ageometric shape comprising a circular shape.
 5. The sleeve device ofclaim 1, wherein one or more of said lower sandwich member and saidupper sandwich member are ring members affixed to said hollow member,wherein said ring members are configured to transfer shear stressesthrough said hollow member to compensate said loss of said shearcapacity of said concrete slab due to said drilled hole.
 6. The sleevedevice of claim 1, wherein said hollow member is configured as anextensible hollow member to be inserted into said drilled hole of aplurality of dimensions and to enable said upper sandwich member andsaid lower sandwich member to adjustably sandwich said concrete slabsurrounding said drilled hole of said dimensions.
 7. The sleeve deviceof claim 1, further comprising a plurality of gripping memberspositioned on and attached to an upper surface of said upper sandwichmember, wherein said gripping members are configured to provide a gripfor engageably connecting said upper sandwich member to said hollowmember.
 8. A sleeve device for compensating loss of shear capacity of aconcrete slab due to a hole drilled in said concrete slab, said sleevedevice comprising: a hollow member inserted into said drilled hole, saidhollow member comprising a threaded upper section extending above a topsurface of said concrete slab; a lower ring member comprising an inneredge rigidly attached to a bottom edge of said hollow member; and anupper ring member comprising an inner threaded edge engageably connectedto said threaded upper section of said hollow member, wherein said upperring member and said lower ring member are configured to sandwich saidconcrete slab surrounding said drilled hole therebetween forcompensating said loss of said shear capacity of said concrete slab dueto said drilled hole.
 9. The sleeve device of claim 8, wherein saidupper ring member and said lower ring member are configured to increasearea of a shear critical section around said drilled hole in saidconcrete slab for compensating said loss of said shear capacity of saidconcrete slab due to said drilled hole.
 10. The sleeve device of claim8, wherein said hollow member is of a generally cylindrical shape. 11.The sleeve device of claim 8, wherein a cross section of said hollowmember is of a geometric shape comprising a circular shape.
 12. Thesleeve device of claim 8, wherein said hollow member is configured as anextensible hollow member to be inserted into said drilled hole of aplurality of dimensions and to enable said upper ring member and saidlower ring member to adjustably sandwich said concrete slab surroundingsaid drilled hole of said dimensions.
 13. The sleeve device of claim 8,further comprising a plurality of gripping members positioned on andattached to an upper surface of said upper ring member, wherein saidgripping members are configured to provide a grip for engageablyconnecting said upper ring member to said hollow member.
 14. A methodfor compensating loss of shear capacity of a concrete slab due to a holedrilled in said concrete slab, said method comprising: providing asleeve device comprising: a hollow member comprising an upper section; alower sandwich member comprising an inner edge rigidly attached to abottom edge of said hollow member; and an upper sandwich membercomprising an inner edge engageably connectable to said upper section ofsaid hollow member; inserting said hollow member of said sleeve deviceinto said drilled hole of said concrete slab to rigidly contact an uppersurface of said lower sandwich member of said sleeve device with a lowersurface of said concrete slab, wherein said upper section of saidinserted hollow member extends above a top surface of said concreteslab; engageably connecting said inner edge of said upper sandwichmember of said sleeve device to said upper section of said insertedhollow member; and sandwiching said concrete slab surrounding saiddrilled hole by said upper sandwich member and said lower sandwichmember of said sleeve device for compensating said loss of said shearcapacity of said concrete slab due to said drilled hole.
 15. The methodof claim 14, wherein said sandwiching of said concrete slab surroundingsaid drilled hole by said upper sandwich member and said lower sandwichmember of said sleeve device comprises: transferring a first shearstress through said concrete slab, thereby producing a first compressiveforce on an upper surface of said lower sandwich member; converting saidfirst compressive force to a second shear stress from said lowersandwich member to said upper sandwich member through a wall of saidhollow member; converting said second shear stress to a secondcompressive force from a lower surface of said upper sandwich member,said second compressive force being transferred to said top surface ofsaid concrete slab; and converting said second compressive force to athird shear stress, said third shear stress being transferred to asupporting column.
 16. The method of claim 14, wherein said uppersandwich member and said lower sandwich member of said sleeve device areconfigured to increase area of a shear critical section around saiddrilled hole in said concrete slab for compensating said loss of saidshear capacity of said concrete slab due to said drilled hole.
 17. Themethod of claim 14, wherein said hollow member of said sleeve device isof a generally cylindrical shape, and wherein a cross section of saidhollow member of said sleeve device is of a geometric shape comprising acircular shape.
 18. The method of claim 14, wherein said hollow memberof said sleeve device is configured as an extensible hollow member to beinserted into said drilled hole of a plurality of dimensions and toenable said lower sandwich member and said upper sandwich member toadjustably sandwich said concrete slab surrounding said drilled hole ofsaid dimensions.
 19. The method of claim 14, wherein one or more of saidlower sandwich member and said upper sandwich member of said sleevedevice are configured as ring members affixed to said hollow member totransfer shear stresses through said hollow member to compensate saidloss of said shear capacity of said concrete slab due to said drilledhole.
 20. The method of claim 14, further comprising providing a gripfor engageably connecting said upper sandwich member of said sleevedevice to said hollow member of said sleeve device by a plurality ofgripping members positioned on and attached to an upper surface of saidupper sandwich member.